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  1. #1
    Join Date
    Jul 2020
    Posts
    3

    Default 06 21v launch 5.7 Indmar Engine upgrade

    Looking for help on improving torque or more power out the hole with riders and a few people on the boat.

  2. #2
    Join Date
    May 2019
    Location
    Arizona
    Posts
    200

    Default

    Quote Originally Posted by Artbjj View Post
    Looking for help on improving torque or more power out the hole with riders and a few people on the boat.
    Might want to start out with a different prop. That would be a lot cheaper than a engine. The 5.7 320hp or 340hp Indmar Assault should be adequate for that boat.


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  3. #3
    Join Date
    Aug 2019
    Location
    St. Louis , MO
    Posts
    135

    Default

    Quote Originally Posted by Turbinesurgeon View Post
    Might want to start out with a different prop. That would be a lot cheaper than a engine. The 5.7 320hp or 340hp Indmar Assault should be adequate for that boat.


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    Absolutely right.

  4. #4
    Join Date
    May 2019
    Location
    Arizona
    Posts
    200

    Default

    Quote Originally Posted by secondsupra2004 View Post
    Absolutely right.
    Yes, yes just like my wife says


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  5. #5
    Join Date
    Jul 2020
    Posts
    108

    Default

    Quote Originally Posted by Artbjj View Post
    Looking for help on improving torque or more power out the hole with riders and a few people on the boat.
    A full rebuild and new prop made mine feel a lot more powerful


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  6. #6
    Join Date
    Aug 2018
    Posts
    3

    Default

    Has anyone tried a tune to upgrade between a MPI 325 to MPI 340?

    Based on the spec the motors look exactly the same, aside from the max RPM. if that's the case, you should be able to unlock some extra HP on the top end with a tune. I found this tuner that claims to do the job.

    https://www.magnumtuning.com/en/deta...ssault-325-mpi

    It would be interesting to try although I'm not sure if I'd what to be the guinea pig, but maybe there is someone out there braver than me .

    Dave

  7. #7
    Join Date
    May 2019
    Location
    Arizona
    Posts
    200

    Default

    Quote Originally Posted by dsthomas05 View Post
    Has anyone tried a tune to upgrade between a MPI 325 to MPI 340?

    Based on the spec the motors look exactly the same, aside from the max RPM. if that's the case, you should be able to unlock some extra HP on the top end with a tune. I found this tuner that claims to do the job.

    https://www.magnumtuning.com/en/deta...ssault-325-mpi

    It would be interesting to try although I'm not sure if I'd what to be the guinea pig, but maybe there is someone out there braver than me .

    Dave
    Come on Dave, don’t be afraid to be a Guinea pig for the Supra team

    This is interesting, website claims 17% power increase taking the Indmar 325 to 380hp and 340 to almost 400hp. I have a 2006 340 in my boat. I believe the differences are intake, throttle body, and computer.
    My concerns are the longevity of the cats. I’m not an expert in tuning so I’d want to make sure this didn’t shorten the life of the cats being how expensive they are to replace.


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  8. #8
    Join Date
    Jun 2012
    Location
    Knoxville TN
    Posts
    1,415

    Default

    Someone on social media was asking about a tuner made in China for $3-400 and wanted to try it on a Raptor Motor that was out of warranty.

    Basically everyone was like: "go ahead and let me know how it goes"
    2018 Supra SL400

  9. #9
    Join Date
    Jul 2020
    Posts
    108

    Default

    I rebuilt my indmar 325 with a decent valve job, mild porting and flat top pistons. I have just over 100 hours on it and it was a huge upgrade. The boat also had nearly 2000 hours on it. It needed it bad. I’d have yours rebuilt. My 06 is a brand new boat to me now. And I’m not lacking power


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